Glassware is sterilized in Hot air oven at –
Hot air ovens use dry heat, right? The core concept here is that dry heat requires higher temperatures and longer times compared to moist heat methods like autoclaving. For glassware, the typical temperature is 160°C for about 2 hours. Let me confirm that. Yes, dry heat sterilization at 160°C for 2 hours is standard for glassware because it effectively kills microorganisms without damaging the glass if done properly.
The incorrect options would be other temperatures. For example, 170°C might be for a shorter time, but the standard is 160°C. 180°C is too high and could damage some glassware. 200°C is even higher and definitely not used. So the correct answer is 160°C for 2 hours.
The clinical pearl here is to remember that dry heat uses higher temps but lower than those for incineration. Also, glassware is preferred over moist heat because it doesn't get corroded. Need to make sure the explanation covers why dry heat is suitable for glass and the specific temperature and time. Also, clarify why other temps are wrong. Let me structure the answer with the required sections. Check for any possible mistakes. Yeah, this should cover it.
**Core Concept**
Dry heat sterilization in hot air ovens relies on high temperatures to denature microbial proteins and oxidize cellular components. Glassware is sterilized using this method because it is heat-resistant and not damaged by prolonged dry heat exposure.
**Why the Correct Answer is Right**
The standard protocol for glassware sterilization in a hot air oven is **160°C for 2 hours**. This temperature effectively kills all microbial life, including spores, by coagulating proteins and disrupting cell membranes. Dry heat requires higher temperatures than moist heat (e.g., autoclaving at 121°C) due to its slower conduction and lack of water-mediated denaturation.
**Why Each Wrong Option is Incorrect**
**Option A:** 121°C is the temperature for autoclaving, which uses moist heat. Dry heat requires higher temperatures.
**Option B:** 170°C may be used for shorter cycles (e.g., 1 hour), but 160°C is the standard for glassware to avoid thermal stress.
**Option D:** 200°C exceeds the tolerance of most glassware, risking shattering or deformation.
**Clinical Pearl / High-Yield Fact**
Remember: **"Dry heat, high heat—160°C for glass in two hours."** Glassware is preferred over metal for dry heat sterilization because metal conducts heat faster and may require lower temps (e.g., 170°C for 1 hour). Always check oven calibration to prevent under-sterilization.
**Correct Answer: C. 160°C for 2 hours**